Waste Management serves virtually all of Alameda County. The company has equipment and sevice facilities in Oakland, Emeryville, Alameda, Hayward, Livermore, Castro Valley, San Lorenzo, Union City and Newark. Other firms haul away trash in Berkeley and Pleasanton.

Shop steward Rudy Esparza of Teamsters Local 70, which represents the nearly 600 garbage truck drivers and operators who work for Waste Management, said his union would honor the mechanics' strike.

That support could hamper Waste Management's attempts to continue garbage pickups today. Esparza acknowledged, however, that the firm has said it planned to have substitute drivers on hand. "I can't believe it," said Alameda County Supervisor Gail Steele, whose district covers half the cities affected by the strike.

"It's a huge section of the county. I consider a strike like this to be extremely serious. It really has an impact on health and safety in the long run" if trash is not picked up, she said.

Waste Management officials could not be reached for comment.

But a company spokesman told KTVU, Channel 2, last night: "We want our machinists back. . . . If they don't show up to work, . . . we're going to get that job done."

Earlier yesterday, members of Local 1546 voted 72 to 8, with two members absent, to reject Waste Management's last offer and authorize the walkout.

Oakland City Councilman Ignacio De La Fuente has attempted to negotiate with the machinists and management late into the evening, an aide said.

Joe Bobo, area director of the machinists' local, said machinists want wage parity with the truckers. Talks had begun in May on the contract that expired at midnight last night.

When that contract had been negotiated in 1993, the machinists received a $1.48-an-hour increase in wages and benefits over four years, while the truckers got a $3.80 increase, Bobo said. Journeyman mechanics earn about $43,000 a year.

The contracts before 1993 were held by Oakland Scavenger, Waste Management's predecessor. Oakland Scavenger, which collected trash from about 1.5 million customers in the East Bay, was acquired by Waste Management in 1986.

"(Oakland Scavenger) was small, like a mom and pop operation," Bobo said. "Most of the people who ran the business were very close to the folks that work there."

But things changed, especially at the negotiating table, after Waste Management took over, Bobo said.

The strike began at midnight, Bobo said, in order to set up picket lines in front of parked garbage trucks, to keep them from being driven away. "We're going to do our best to make sure they don't move," he said.

Bobo also said he saw "no reason" why the Teamsters would not support the strike.

In April, a strike by San Francisco's garbage collectors was resolved in two days with help from Mayor Willie Brown. Members of Sanitary Drivers and Helpers Local 350 had struck Norcal Waste Systems.

Norcal supervisors and the few workers who did not honor union picket lines made limited collection runs during the strike. Despite those efforts, company officials estimated they collected only about 700 tons of garbage while the strike was under way -- a fraction of the 2,300 daily tons Norcal picks up under normal conditions.

Although tons of refuse piled up during the two-day walkout, the strike was over so quickly that rodent infestation and sanitation problems feared by the city's public health officials did not materialize. Dr. Sandra Hernandez, the city's director of public health, said the strike resulted only in a "public nuisance," not a public health emergency.